Abstract: The devastating tsunamis that struck Chile and Japan in 2010 and 2011 underscored the critical need for new structural design criteria to improve building resilience and safeguard human life. They also provided a wealth of information that could form the basis for estimating tsunami loads and effects and guiding the development of a design methodology. A team of researchers and practitioners took up the challenge, which resulted in the inclusion of provisions for tsunami loads in Standard ASCE/SEI 7-16, Minimum Design Loads and Associated Criteria for Buildings and Other Structures.For many US structural and geotechnical engineers, ASCE 7-16's provisions and commentary will be their first exposure to tsunami design. In this companion guide, author Ian Robertson helps engineers and allied professionals understand the background and development of the new provisions. He guides them through the application of tsunami design with a series of clear and detailed examples based on prototypical buildings. He connects the ASCE 7-16 tsunami provisions to prior design guidelines, laboratory research, and field surveys. In addition, he explains the key concepts in the provisions, including tsunami risk categories; inundation depth and flow velocities; structural design procedures; and hydrostatic, hydrodynamic, and debris impact loads. Robertson demonstrates the application of these concepts in numerous examples and a full-length tsunami design of a prototype building. The guide also explains the tsunami provisions for foundation design, structural countermeasures, vertical evacuation refuges, nonstructural components and systems, and critical nonbuilding structures.Tsunami Loads and Effects: Guide to the Tsunami Design Provisions of ASCE 7-16 is a clear and authoritative explanation of the tsunami load requirements that will be welcomed by structural, coastal, and geotechnical engineers, as well as architects, building code officials, contractors, and emergency managers

Author Ian Robertson provides a comprehensive, authoritative guide to the new tsunami design provisions of Standard ASCE/SEI 7-16 using a series of detailed examples based on prototypical buildings.

Standard ASCE/SEI 7-22 provides requirements for general structural design and includes means for determining various loads and their combinations, which are suitable for inclusion in building codes and other documents.

Sponsored by the Structural Engineering Institute of ASCE. On March 11, 2011, at 2:46 p.m. local time, the Great East Japan Earthquake with moment magnitude 9.0 generated a tsunami of unprecedented height and spatial extent along the northeast coast of the main island of Honshu. The Japanese government estimated that more than 250,000 buildings either collapsed or partially collapsed predominantly from the tsunami. The tsunami spread destruction inland for several kilometers, inundating an area of 525 square kilometers, or 207 square miles. About a month after the tsunami, ASCE?s Structural Engineering Institute sent a Tsunami Reconnaissance Team to Tohoku, Japan, to investigate and document the performance of buildings and other structures affected by the tsunami. For more than two weeks, the team examined nearly every town and city that suffered significant tsunami damage, focusing on buildings, bridges, and coastal protective structures within the inundation zone along the northeast coast region of Honshu. This report presents the sequence of tsunami warning and evacuation, tsunami flow velocities, and debris loading. The authors describe the performance, types of failure, and scour effects for a variety of structures: buildings, including low-rise and residential structuresrailway and roadway bridgesseawalls and tsunami barriers breakwaterspiers, quays, and wharvesstorage tanks, towers, and cranes. Additional chapters analyze failure modes utilizing detailed field data collection and describe economic impacts and initial recovery efforts. Each chapter is plentifully illustrated with photographs and contains a summary of findings. For structural engineers, the observations and analysis in this report provide critical information for designing buildings, bridges, and other structures that can withstand the effects of tsunami inundation.

Past tsunami events were reviewed with the objective of evaluating observed structural response. Selected structures are described and used to evaluate the performance of different structural systems and materials during a tsunami event. In general, only engineered structural steel and reinforced concrete structures, and structures raised above the tsunami flow, were able to survive the tsunami forces without collapse or substantial structural damage.

FEMA initiated this project in September 2004 with a contract to the Applied Technology Council. The project was undertaken to address the need for guidance on how to build a structure that would be capable of resisting the extreme forces of both a tsunami and an earthquake. This question was driven by the fact that there are many communities along our nation's west coast that are located on narrow spits of land and are vulnerable to a tsunami triggered by an earthquake on the Cascadia subduction zone, which could potentially generate a tsunami of 20 feet in elevation or more within 20 minutes. Given their location, it would be impossible to evacuate these communities in time, which could result in a significant loss of life. Many coastal communities subject to tsunami located in other parts of the country also have the same potential problem. In these cases, the only feasible alternative is vertical evacuation, using specially design, constructed and designated structures built to resist both tsunami and earthquake loads. The significance of this issue came into sharp relief with the December 26, 2004 Sumatra earthquake and Indian Ocean tsunami. While this event resulted in a tremendous loss of life, this would have been even worse had not many people been able to take shelter in multi-story reinforced concrete buildings. Without realizing it, these survivors were among the first to demonstrate the concept of vertical evacuation from a tsunami. This publication presents the following information: General information on the tsunami hazard and its history; Guidance on determining the tsunami hazard, including the need for tsunami depth and velocity on a site-specific basis; Different options for vertical evacuation from tsunamis; Determining tsunami and earthquake loads and structural design criteria necessary to address them; and, Structural design concepts and other considerations. In September 2004 the Applied Technology Council (ATC) was awarded a “Seismic and Multi-Hazard Technical Guidance Development and Support” contract (HSFEHQ-04-D-0641) by the Federal Emergency Management Agency (FEMA) to conduct a variety of tasks, including the development of design guidance for special facilities for vertical evacuation from tsunamis, which ATC designated the ATC-64 Project. The effort was co-funded by FEMA and the National Oceanic and Atmospheric Administration (NOAA). The developmental process involved a variety of activities including review of relevant research and state-of-the-practice documentation and literature, preparation of technical guidance and approaches for tsunami-resistant design, identification of relevant tsunami loads and applicable design criteria, development of methods to calculate tsunami loading, and identification of desired architectural and structural system attributes for vertical evacuation facilities. The resulting guidance for design of special facilities for vertical evacuation from tsunami, as presented herein, addresses a range of relevant issues. Chapter 1 defines the scope and limitations of the guidance. Chapter 2 provides background information on tsunami effects and their potential impacts on buildings in coastal communities. Chapters 3 through 7 provide design guidance on characterization of tsunami hazard, choosing between various options for vertical evacuation structures, locating and sizing vertical evacuation structures, estimation of tsunami load effects, structural design criteria, and design concepts and other considerations. The document concludes with a series of appendices that provide supplemental information, including examples of vertical evacuation structures from Japan, example tsunami load calculations, a community design example, development of impact load equations, and background on maximum flow velocity and momentum flux in the tsunami runup zone.